Search

This study sought to clarify whether suspended particles containing high Cu concentrations are present in the sea-surface microlayer (S-SML). For this reason, suspended particles (10–2000 μm) in the S-SML were collected periodically from a ship mooring pond during 2018–2020, and the acid-soluble Cu concentration in the suspended particles was measured as particulate Cu (P-Cu). The highest concentration of P-Cu in the S-SML of the pond was 75 μg L−1 with a 90th percentile value of 2.5 μg L−1. This is below P-Cu values reported for the S-SML in North American ports, but 140 times higher than this found in bulk seawater in the Atlantic Ocean. The highest P-Cu concentration in the S-SML of non-organism (abiotic) origin was 17 μg L−1, and the abiotic P-Cu to P-Cu ratio varied from 0.2 to 100%, likely depending on the quality and quantity of biogenic material in the S-SML samples. It is assumed that the S-SML particles examined here contain high Cu concentrations originating from ship antifouling paints.

Graphical abstract, Environmental structure describes physical structure that can determine heterogenous spatial distribution of biotic and abiotic (nutrients, stressors etc.) components of a microorganism’s microenvironment. This study investigated the impact of micrometre-scale structure on microbial stress sensing, using yeast cells exposed to copper in microfluidic devices comprising either complex soil-like architectures or simplified environmental structures. In the soil micromodels, the responses of individual cells to inflowing medium supplemented with high copper (using cells expressing a copper-responsive pCUP1-reporter fusion) could be described neither by spatial metrics developed to quantify proximity to environmental structures and surrounding space, nor by computational modelling of fluid flow in the systems. In contrast, the proximities of cells to structures did correlate with their responses to elevated copper in microfluidic chambers that contained simplified environmental structure. Here, cells within more open spaces showed the stronger responses to the copper-supplemented inflow. These insights highlight not only the importance of structure for microbial responses to their chemical environment, but also how predictive modelling of these interactions can depend on complexity of the system, even when deploying controlled laboratory conditions and microfluidics.

The modern metals industry is characterised by a downward trend in the quality of ores involved in processing, and conventional methods of extracting useful components are inefficient for raw materials with complex composition. To maintain the growing level of metal production it is required to introduce new efficient technologies for processing of low-grade and refractory ores as well as man-made deposits. The article describes processing methods of refractory raw materials with high cyanide content using copper-gold ores as an example, where gold is the primary commodity, and copper is the accompanying useful component. The most common method of processing copper-gold ores is preconcentration followed by selective leaching of copper and gold. In some cases, technologies involving copper by-products and cyanide recovery from the cyanide leaching solutions offer equally effective options for processing of the copper-gold ores and concentrates. Copper-gold ores are processed at gold mines using the cyanide procedures, supplemented if required by gravity and flotation concentration. In all variations of the cyanide treatment, most of copper minerals actively react with cyanides of alkali metals, binding the CN– ions into the copper complex of [Cu(CN3)]2–. This reaction results in an increased solvent consumption, as well as in number of challenges related to cleaning tailings and slurries from highly toxic cyanide compounds and dissolved copper. In addition to technological complications associated with the need to meet strict requirements for the maximum permissible concentrations, copper accumulated in the cycling solutions also causes a decrease in gold extraction from the processed ores.

To further investigate the influence of temperature and copper content on the carbon brush on the current-carrying friction of the carbon brush/friction disc contact pair. In this paper, the wear performance of five carbon brushes with different copper contents at two types of temperatures was discussed. The tests were carried out on a pin-disc type wear tester with a heating system. The results show there is a critical copper content that affects the friction performance of carbon brushes by influencing the integrity of the friction film. As the test temperature increases, the wear rate of the test samples in the high copper content group increases dramatically.

This study aims to determine both short- and long-term response of enriched anammox culture to Cu. Assessment of short-term inhibition is based both on total applied Cu concentration and potential bioavailable fractions like intracellular, surface-bound, soluble and free Cu ion. The half maximal inhibitory concentration (IC50) values for total applied, soluble, intracellular and cell-associated concentrations were determined as 4.57 mg/L, 1.97 mg/L, 0.71 mg/L, 1.11 mg/L, respectively. Correlation between the surface-bound fraction of Cu and inhibition response was weak, suggesting that Cu sorbed to biomass was not directly responsible for the effects on anammox activity. There was a disparity between the results of short- and long-term experiments in terms of inhibition threshold concentration (i.e. short-term IC50 = 4.57 mg/L vs long-term IC50 = 6.74 mg/L). Candidatus Kuenenia (59.8%) and Candidatus Brocadia (40.2%) were the two main anammox genera within the initial biomass sample. One of the most interesting finding of the study is the demonstration that a complete wash-out of C. Brocadia genus at an applied Cu concentration of 6.5 mg/L. This strongly indicates that C. Brocadia were not able to tolerate high copper concentrations and all nitrogen conversion was carried out by C. Kuenenia during the Cu exposure period.

The evolution of microstructure and the variation of strain field induced by precipitation in Al–Si–Mg–Cu alloy with high copper content during early ageing is characterised by high-angle annular d...

Gold recovery process is well known. The following paper presents the problematic related to the influence of Copper and Arsenic on the recovery of gold in the Yalea deposit. Multielement tests (Au, Cu, As) carried out on 37 blocks made it possible to understand that there is a correlation between these elements. This correlation has been observed since the analysis of block models (the block model for Copper, block model for Arsenic and the block model for gold. These models have shown that the Yalea deposit areas with a high gold content correspond to areas of high copper content and arsenic. Those who made it clear that copper and Arsenic are tracing elements of Gold in the Yalea deposit. In this paper, the mineralurgical tests carried out on 28 blocks revealed that the copper and the arsenic content in the ore penalize the recovery of Gold (146 ppm for copper and 4710 ppm for Arsenic). The Yalea deposit was emplaced by several hydrothermal phases that reactivated the structures. These phases are responsible for the establishment of large quantities of copper sulphides. Copper and Arsenic are elements that have a considerable influence on the gold recovery in the Yalea deposit.

This paper describes the test methods that were applied to three ingots of high-copper converter matte with the weight ratio of Cu:Ni ~ 2.3 at Polar Division of PJSC MMC Norilsk Nickel to determine their cooling rate. The obtained results are also discussed. A test heat was done in the converter of the Nadezhdinski Metallurgical Plant, during which the following compositions were closely monitored: that of middlings; that of the finished matte that was discharged at 1,255–1,260 оС and poured in molds at 1,200 and 1,140 оС; and that of metallized matte that was intentionally overheated to 1,285–1,290 оС and poured at 1,200 оС. The cooling time was 82 and 93 hours (for capped ingots). The temperature was monitored with the help of six chromel-alumel thermocouples located at the level of 1,350, 850 and 350 mm from the bottom; three of them in the centre and the other three on a side. The ingots were crushed at the Nickel Plant, and a ~300 kg representative sample with the size of 3 mm was taken from each ingot for flotation tests. Spot samples were taken from the temperature monitoring areas for structural characterization. Based on experimental data, functional dependencies were derived with R2 0.99 that describe the obtained cooling curves. It is shown that due to the use of insulation cap in the structure defining temperature range of 1,150–750 оС, the cooling rate of the ingot top can be considerably decreased (approximately by three times). It is equal to 28–29 оС/h. In the vertically central part of all test ingots — i. e. ~850 mm from the bottom both in the centre and on a side, the cooling rates vary in the range of ~9–10.5 оС/h; in lower monitoring points — i. e. 350 mm from the bottom, they are equal to 24–33 оС/h. The cooling rate of the overheated matte at the top drops to 67 versus 87 оС/h for the uncapped ingot, whereas in the centre and at the bottom it almost remains the same.

The paper presents the results of the development of a special group of cast composite materials based on nodular cast irons. The alloys were based on alloying cast iron with copper in amounts that exceed its solubility in liquid Fe-C-Si systems (Cu>6 wt.%). A new component is obtained in the structure of castings in the form of a complex mixture based on the Cu-phase. Inclusions are relatively large (up to 200 μm) and globular in shape, with a uniform allocation in the volume of the castings. This favorably distinguishes the obtained alloys from the known cast irons and gives them high antifriction properties. With isothermal hardening, it is possible to obtain the lowest values of wear for structures of lower bainite. Developed cast composite materials are recommended to be used as tribotechnical materials working in conditions of poor lubrication and corrosion.

This study investigated the relationship between subjective forgetfulness and the dietary intake of various nutrients in middle‐aged and senior women. A cross‐sectional study of the first‐visit records of 245 Japanese women aged 40 or over was performed. The severity of subjective forgetfulness was classified according to the Menopausal Health‐Related Quality of Life Questionnaire: none and mild (“unforgetful”) or moderate and severe (“forgetful”). Dietary consumption of nutrients was estimated using the brief‐type self‐administered diet history questionnaire. The associations between the severity of subjective forgetfulness and intake of 43 major nutrients were evaluated using multivariate logistic regression analysis separately performed for two age groups: middle‐aged (40–54 years, N = 166) and senior (55 years or over, N = 79). No nutrients were found to be significantly associated with subjective forgetfulness in the middle‐aged group. In senior women, a significant positive relationship between the intake of copper and forgetfulness was found (adjusted odds ratio per 10 mg/kJ increase in copper intake: 1.25; 95% confidence interval: 1.08–1.50). Thus, high copper intake is positively associated with the severity of forgetfulness in Japanese senior women. Reducing copper consumption could help improve this symptom in this population., We examined the nutritional factors associated with subjective forgetfulness. Participants were Japanese middle‐aged and elderly women. High copper intake is positively associated with the severity of forgetfulness in Japanese senior women.

Os metais são reconhecidos pelo caráter potencialmente tóxico às comunidades além de bioacumulativos em alguns organismos. No presente trabalho, avaliou-se as concentrações dos metais cádmio, cromo, cobre, chumbo, mercúrio e zinco em sedimentos de três pontos de amostragem nos reservatórios Billings, Guarapiranga e Rio Grande (São Paulo, Brasil) entre os anos 2008 e 2017. Os dados foram comparados à valores de referência regionais, à legislação local e a valores guia de qualidade de sedimento: nível de efeito limiar (TEL), nível de efeito provável (PEL) e Critérios de Avaliação dos Sedimentos (CQS). Amostras de sedimento do reservatório Billings apresentaram os maiores números de metais acima dos valores de referência e acima de PEL. Observou-se elevadas concentrações de cobre nos reservatórios Guarapiranga e Rio Grande, provavelmente em decorrência do sistema de gestão aplicado no local à base de Sulfato de Cobre Pentahidratado. Os dados analisados aqui, indicam que a falta de índices regionalizados, com valores de background e critérios de toxicidade para o sedimento, específicos para esses reservatórios é uma grande deficiência para análises mais acuradas e preditivas. Ainda assim, fica demonstrado que os níveis atuais de contaminação dos sedimentos dos reservatórios estão reduzindo a qualidade da água e pressionando negativamente a biota local e alterando e comprometendo o ecossistema aquático.

Introduction. The mining and metallurgical industries form the basis of the economy of the Murmansk Region. Working conditions at industrial enterprises, combined with extreme climatic conditions of the Arctic, pose an increased risk of occupational diseases. The purpose of the study was to investigate working conditions and occupational disease rates among industrial workers of the Murmansk Region in 2007–2017. Materials and methods. We studies socio-hygienic monitoring data on working conditions and occupational diseases in the population of the Murmansk Region in 2007-2017 provided by the Federal Center for Hygiene and Epidemiology of the Federal Service for Supervision of Consumer Rights Protection and Human Welfare, Moscow. Results. In 2008-2017, the most common occupational risk factors in the Murmansk Region included noise (25.8%), job strain (17.8%), and chemical factor (12.6%) while 39.2% of workers were exposed to a combination of occupational hazards. Over 10 years, the absolute number of workers exposed to dangerous and hazardous industrial factors decreased by 1.8 times. In the Murmansk Region, 84.3% of occupational disease cases were registered among workers of mining and metallurgical enterprises. In 2007-2017, the region experienced a significant decrease in occupational disease incidence mainly related to job cuts. The role of other factors (improvement of working conditions, health promotion) needs to be clarified; yet, it is possible to predict their positive influence on occupational morbidity in the next few years. Conclusion. To achieve a substantial decrease in occupational disease incidence rates, it is essential to keep improving comprehensive measures aimed at preserving workers’ health in the Murmansk Region.

In spite of their similar structures, the catalytic properties of natural and synthetic (SSZ-13) Chabazite during the selective reduction of NO with NH3 have a different dependence on the Cu exchange level when tested under conditions equivalent to those found in Diesel vehicles. At low (1-2 wt.%) and high copper loadings (6-14 wt.%), their activities differ, because there are variations in the different species of Cu (Cu+, Cu2+, Cu-O-Cu) detected by UV-Vis. At intermediate Cu loadings (2-3 wt.%) they have similar high activities, reaching 100 % conversion. High deNOx activity per Cu site appears to correlate with the predominance of charge compensation Cu2+ species over CuOx moieties. There are changes in the distribution of Cu moieties during operation of both catalysts, evidenced by DR-UV-Vis. Resumen. A pesar de sus estructuras similares, las propiedades catalíticas de Chabazita natural y sintética (SSZ-13) durante la reducción selectiva de NO con NH3 dependen de manera diferente frente al nivel de intercambio con Cu cuando se prueban bajo condiciones equivalentes a las de vehículos Diesel. A bajos (1-2 % p/p) y altos contenidos de Cu (6-14 % p/p) la reducción de NO es diferente debido a variaciones en las distintas especies de Cu (Cu+, Cu2+, Cu-O-Cu) observadas por UV-Vis. Por su parte, los catalizadores intercambiados con 2-3 % p/p de Cu tuvieron alta actividad por sitio de Cu, alcanzando 100 % de conversión de NO, lo que parece deberse a la predominancia de especies de Cu2+ sobre especies CuOx de acuerdo con el análisis por DR-UV-Vis, el que también muestra la existencia de variaciones en la distribución de especies de Cu debido a la reacción.

International audience; This article aims to assess the impact of copper availability on the energy transition and to determine whether copper could become critical due to the high copper content of low-carbon technologies compared to conventional technologies. In assessing copper availability through to 2050, we rely on our linear programming world energy-transport model, TIAM-IFPEN. We examine two climate scenarios (2 °C and 4 °C) with two mobility shape, implemented with a recycling chain. The penetration of low-carbon technologies in the transport and energy sectors (electric vehicles and low-carbon power generation technologies) is likely to significantly increase copper demand by 2050. To investigate how tension over copper resources can be reduced in the energy transition context, we consider two public policy drivers: sustainable mobility and recycling practices. Results show that in the most stringent scenario, the cumulative primary copper demand between 2010 and 2050 is found to be 89.4% of the copper resources known in 2010. They also pinpoint the importance of China and Chile in the future evolution of the copper market.

We discovered previously that Formosan squirrels (Callosciurus erythraeus) accumulate copper (Cu) in their livers at levels averaging 1700 μg per dry g (approximately 420 μg per wet g). In the current study, we investigated the relationship between Cu accumulation and hepatic injury, and we determined the distribution and chemical form of Cu in the liver supernatant. In particular, we explored the role of metallothionein in the liver supernatant. We observed no significant differences in hepatic Cu concentration between squirrels that showed pathological changes in the liver and those that did not. Serum alanine aminotransferase activity did not increase with increasing hepatic Cu concentration. These results suggest that abnormal Cu accumulation in the livers of Formosan squirrels does not induce severe hepatic injury. We found that 26.7% of the Cu in the liver was distributed to the supernatant, and only 11.0% of the Cu in the liver was bound to metallothionein, suggesting that metallothionein in the hepatic supernatant does not contribute to detoxification of excess Cu in Formosan squirrels.

The metal mining activity has been the source of large volumes of tailings that must be stored in tailings storage facilities (TSFs). Since tailings might contain residual valuable metals, these are often subject of assessment studies aimed to find a feasible way to reprocessing. One of these TSFs was built and operated during the 1930’s for the exploitation of a giant porphyry copper deposit in Chile, a deposit that is still under exploitation today. For these old tailings a historical assessment was varied out about the copper recovery potential in a reprocessing scenario by flotation. Based on theoretical concepts and available historical operational data, it can be shown that the main reason for the relatively high copper grades found in these tailings are the corresponding high grades of the processed ores, instead of being the result of an inefficient past technology of flotation with consequential low recoveries. Conversely, the former flotation circuit was optimal concerning the recovery of copper sulphides favoured by the less restrictive high copper content of these sulphides. Consistently, it is argued for the study case that the main advances in flotation circuits have focused on improving selectivity without sacrificing recovery, due to the changes in the mineralogy of the exploited ores. These are relevant facts for a reprocessing scenario, indicating a low copper recovery potential if the current conventional flotation technology is considered; thus other and/or newer processing technologies could be more efficient for recovery of the remaining copper. There are hydrometallurgical potential alternatives for reprocessing but limitations are expected in relation to milling size of the tailings material. The present findings may apply elsewhere, due to the high representativeness of the present study case.

A handheld XRF-analyzer specially calibrated for measurements of metals on plastic boat hulls has been used on leisure boats in Denmark (DK), Finland (FI), and Germany (DE). The results on tin and copper are presented as μg metal/cm2. Tin is a proxy for the occurrence of organotin compounds on the boat. Two or three sites were visited in each country and between 25 and 90 boats were measured at each site. Every boat was measured at six to eight places, and the results are presented both as mean and median values. Linear regression of mean to median values of the 377 data pairs shows high relationship with R2 = 0.9566 for tin and R2 of 0.9724 for copper and thus both ways of calculation may be used. However, for regulative use, it is suggested that all individual measurements on each boat should be presented and used for decisions of removal or sealing of boat hulls. The results are compared with published data from different parts of Sweden, i.e., boats in fresh water, brackish water, and salt water. The results show that tin with mean values > 50 μg Sn/cm2 is still found on 42, 24, and 23% of the boats in DK, FI, and DE, respectively. The corresponding percentages based on median values are 38, 22, and 18% for DK, FI, and DE, respectively. The variation among boats is high with a maximum mean value of 2000 μg Sn/cm2. As comparison, one layer of an old TBT antifouling paint Hempels Hard racing superior, corresponds to 300 μg Sn/cm2. The percentage of boats with tin > 400 μg Sn/cm2 content based on mean values was 10% in DK, 5% in FI, and 1% in DE. The corresponding median values were 9, 6, and 1% for DK, FI, and DE. Copper, > 100 μg Cu/cm2, was detected on all measured boats in DK and in DE and on all but 3% of the FI boats. One layer of Hempels MilleXtra corresponds to ~ 4000 μg Cu/cm2. The recommendation on the can is to apply two layers. The proportion of boats with higher mean copper values than 8000 μg Cu/cm2 was 51, 56, and 61 for boats in DK, FI, and DE, respectively. The proportion based on median values > 8000 μg Cu/cm2 was 50, 54, and 61% for DK, FI, and DE. The conclusion is that many leisure boats around the Baltic Sea still display or possess antifouling paints containing organotin compounds and that more than half of the boats have more copper than needed for one boat season according to the paint producers. Much of these known toxic compounds will probably be released into the environment and harm the biota. The calibrated XRF-method, intended for area measurements on boat hulls, is an easy and cheap way to detect boats with organotin compounds and high copper content. We recommend environmental authorities to use this method for identification of such boats and to use the results for requesting measures to minimize further leakage to the environment.

the main goal of this present investigation is to study the effect of the (Al2O3) addition on corrosion resistance and dimensional change of the high copper dental amalgam. One alloy has been prepared via casting composed of silver (47%), tin (30%), copper (22%), and zinc (1%). (Al2O3) addition is added in distinct percentages of the (0.5, 1, 1.5, 2) wt.%. Specimens were prepared according to ADA specification No. 1. The specimens have been stored at 37±1 C° using a chamber prepared for this purpose. corrosion resistance improved with addition from 0.5% to 2% (Al2O3) and observed that dimensional change of amalgam improved after (Al2O3) additions.

The influence of ammonium humate obtained from peat on the tolerance of wheat plants to high CuSO4 concentrations (100, 250, 500, and 1000 μM/L) has been studied. Seeds were germinated on a copper sulfate solution with and without the humate. Then the plants were grown on Hoagland’s solution in an artificial climate chamber. The coefficient of protective action by humate was estimated in the following two ways: by dry weight changes and by the copper ion content in comparison with the plants grown without humate. The protective role of the humate at 100 and 250 μM has been established, which is due to reduction of copper accumulation in the plants. It has been found that the humate at higher concentrations enhances the toxic effect of copper.

The ability of soft rot fungi possessing strong (Phialophora malorum), medium (Phialophora mutabilis) and poor copper tolerance (Chaetomium globosum) to degrade untreated and CuSO4 and micronized copper treated birch- and pine wood was assessed using ENV 807 standard tests. The aim was to determine whether an ability to grow on Cu-agar and copper in liquid cultures can be transcribed into a competitive advantage to degrade Cu-treated wood. An ability to tolerate high copper levels in-vitro was not correlated with increased decay by the fungi but rather reflected the native chemistry of the wood cell walls. Both untreated and Cu-treated wood were degraded by the three fungi and showed aggressiveness in the order C. globosum > P. mutabilis > P. malorum Higher mass loss was recorded for birch than pine and decreased progressively as the copper loadings increased with statistically insignificant difference noted between Cu-treatments. Microscopy showed decay at the cell wall level to reflect degree of lignification with parenchyma cells degraded first in both untreated and Cu-treated wood. Results indicate presence of copper and its toxicity is unlikely to be the main reason for preventing soft rot decay of wood but rather the additive effect of copper binding to the wood material.

In the restoration of lost or damaged dental pieces, different alloys are frequently used, leaving the mouth exposed to electrical currents that circulate through saliva and dental fluids. In the present work, electrochemical methods are used to determine the corrosion rate of galvanic pairs of a high copper silver amalgam with Co-Cr dental alloys in artificial saliva. It is observed that when the difference in corrosion potentials of dissimilar alloys are small (less than 100 mVecs), Evans diagrams do not give good results, so the Mansfeld correction formulas must be used. Thus, it is found that the most resistant to corrosion is the pair formed between the amalgam and the bulk Co-Cr alloy (PG1,3) and that the corrosion products released in greater quantity to the electrolyte are those that contain ions of Co, Cr, Ag, Sr and Cu. Keywords: Corrosion, dental alloy, polarization curve, artificial saliva, galvanic pair.

Vineyards in southern Brazil have high copper levels due to the application of products to control fungal diseases. High soil concentrations of this element can have toxicity to young plants. Arbuscular mycorrhizal fungi (AMF) can alleviate this effect, but the beneficial effect depends on the plant and AMF. AMF have different ecological strategies and respond differently to environmental and management variables. We analyzed AMF species richness, root mycorrhizal colonization, and soil physicochemical attributes in soil and grapevine root samples from vineyards with different growing times (

This study aims to reveal features of the local crystal structure and environment in the quasi-binary TiNi–TiCu alloys containing 25–40 at.% Cu, by X-ray diffraction and EXAFS spectroscopy. The alloys were produced in an amorphous state by the melt-spinning technique and then crystallised by isothermal and electropulsing treatment. It was shown that Ni local structure is more disordered in comparison with Cu local environment, which is closer to the conventional crystallographic structure. An increase in the Cu content resulted in the magnification of the disordering in the nearest local environment, around both the Ni and Cu atoms, consisting of Ti atoms. No noticeable effect of the annealing rate on the local structure was found.

Pulau Kampai is the name of a small island on the east coast of Sumatra and also the name of a village on this island. Excavations conducted at Pulau Kampai in the mid-1970s yielded glass beads likely manufactured in India. More glass beads dating from the 11th to the 14th c. AD were found during excavations undertaken more recently. Those beads were analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Results show that the vast majority of the beads were likely imported from South Asia. Trace element signatures point toward two production areas: western India for most of the beads and northeastern India for a few high copper orange and red beads. A small number of beads have a very different composition resulting from the use of soda plant ash and a low alumina silica source indicating a possible Middle-Eastern provenance. A comparison with data published elsewhere indicates a similarity with material found in Egypt, dating from the 13th to the 15th c. AD suggesting that those beads might have reached the island during the later phases of the occupation period and might have transited through Egypt. It is uncertain where those beads were manufactured within the Middle-East. A comparison is provided with the glass beads from the site of Kampung Sungai Mas (9th to the 11th c. AD) located in Malaysia, one of the only “late” sites in the area that was studied recently using LA-ICP-MS.

The cooperative interactions between chalcopyrite and bornite during bioleaching by mixed moderately thermophilic culture were investigated mainly by bioleaching experiments and electrochemical experiments. Bioleaching results showed that a cooperative effect existed between chalcopyrite and bornite. When the mass ratio of chalcopyrite to bornite was 3:1, an extremely high copper extraction of more than 88% was achieved after bioleaching for 27 days. One of the major reasons for the cooperative effect was that a certain redox potential range (370–450 mV vs. Ag/AgCl) could be maintained for a long period of time during bioleaching due to the mixture of chalcopyrite and bornite. Electrochemical measurements revealed that chalcopyrite was much easier to be reduced than oxidized, while bornite was prone to be directly oxidized. Hence, galvanic effect between chalcopyrite and bornite enhanced the reduction of chalcopyrite to secondary copper-iron species and promoted the oxidative dissolution of bornite. Therefore, redox potential controlling and galvanic effect both contributed to the cooperative bioleaching of chalcopyrite and bornite.

A coated copper sulfate algicide designed for controlled release of copper was evaluated for its effectiveness in controlling phytoplankton in hybrid catfish, ♀Ictalurus punctatus × ♂Ictalurus furcatus, ponds. Copper concentrations were greater in ponds receiving weekly treatments with copper sulfate crystals than in ponds in which the coated copper sulfate was suspended in porous bags and left in ponds during the study. However, the coated copper sulfate treatment provided a similar degree of phytoplankton control for a period of about 4 mo. Copper additions did not negatively affect catfish survival, production, or feed conversion in either the copper sulfate crystal treatment or in the coated copper sulfate treatment as compared with the control (P > 0.05). Flavor scores for fish did not differ between control and treatments (P > 0.05). The coated copper sulfate appeared to be a potentially effective method for controlling phytoplankton in aquaculture ponds. It would be easier to apply and require fewer applications, and the coated copper algicide would not present a fish toxicity issue that can arise from high copper concentration immediately following copper sulfate crystal treatment.

The selective catalytic reduction of NOx with NH3 was investigated over microstructured reactors based on Cu/Al2O3 films deposited onto stainless steel microgrids. The catalytic activity results showed that these Cu/Al2O3 films were more active and selective to produce N2 compared to the conventional catalysts in powder shape with the same copper loadings. The difference was explained by combined features provided by the microstructured catalysts such as the high acid character of the catalytic films, the high copper species dispersion, the nature of the metallic microreactor and its geometric configuration.

The paper presents results of research of the content of zinc, copper, lead, cadmium and selenium in hair of 236 native persons aged 1-6 years of some regions of northern European in Russia: in the city Inta and town Troitsko-Petschorsk of the Komi Republik and in the town Plesetsk of Arkhangelsk region. Research showed that the content of trace elements in hair of examined children differ from each other and the norm for the midland of Russia. Almost 50% of children of the city Inta the content of zinc in hair is lowered. All the studied places are characterized by high copper content: in Inta - for 71 % of preschool children, in Troitsko-Petschorsk - for 53 %, in Plesetsk - for 74 %. The content of lead at children in Inta and Troitsko-Petschorsk exceeds the norm. More than half of the examined children of Inta have an excess of lead. It can be connected with an environmental situation and the characteristics of geochemical provinces of Northern European. Connections between content of some trace elements in organism and development of diseases have been analyzed.

Purpose The presence of high copper (Cu) and cadmium (Cd) contamination in soils around mining areas has raised serious health concerns. Improving hydroxyapatite (HAP) adsorption capacity for Cu and Cd is important if its application potential in heavily contaminated soils is to expand.

In the process of cyanidation of gold concentrate from a smelting company, the content of copper and zinc in the liquid gradually increased. In production, acidizing process is used to treat the lean solution from high copper concentrate, and mixed products containing copper, zinc and other metals are produced. In this paper, the pH value of zinc precipitation is 6.0 and the pH value of copper precipitation is 3.0 through theoretical calculation and experiment. The separation of copper and zinc in the lean solution is realized successfully. The zinc product with grade of 42.97% and the copper product with grade of 58.33% are produced.

Thin materials exhibiting the shape memory effect, with a narrow temperature hysteresis, are required to create miniature and high-speed devices. Quasi-binary intermetallic TiNi-TiCu alloys with high copper contents (more than 10 at %) demonstrate the reversible martensitic transformation with a small (4-6 K) hysteresis. Alloys of the TiNi–TiCu system with a copper content of 30–40 at.% were fabricated in an amorphous state by the planar flow casting technique at a melt cooling rate of 106 K/s in the form of ribbons 30–50 μm thick. The alloy samples were subjected to dynamic crystallization using a single electric current pulse with duration of 5 ms. X-ray diffraction studies revealed almost fully martensitic state of the alloys with B19 structure at room temperature. TEM examination showed their structure to contain typical B19-martensite plates with a mean size of 20–80 nm. At the same time, the alloys exhibit a one-stage phase martensitic transformation B2↔B19 in the temperature range of (55÷75)°C, as well as pronounced shape memory effect, whose properties are largely determined by the structural parameters of the alloys.

The rapidly quenched alloys of the quasibinary intermetallic TiNi-TiCu system with a high copper content (more than 25 at.%) are of great interest as shape memory materials due to the possibility of a significant decrease in the temperature and deformation hysteresis in comparison with the binary TiNi alloy. To obtain alloys with a copper content of 25 to 40 at.%, the planar flow casting technique was used. The alloys were fabricated at a melt cooling rate of about 106 K/s in the form of ribbons 30-50 μm thick and wide in the range from 7 to 20 mm. The study of the structure of the alloys was carried out using X-ray diffraction analysis, scanning and transmission electron microscopy. It was shown that from the ribbon side, contacting the quenching wheel, all alloys are amorphous, while on the non-contact side of the ribbons of alloys with 25 and 30 at.% Cu, a thin surface crystalline layer with a B2 structure is observed. Using energy dispersive X-ray spectroscopy, it was found that the content of the alloy components in the amorphous and crystalline phases coincides.

Nanoscale Cu-rich precipitates that were formed in Cu-containing reactor pressure vessel (RPV) steels during service have a deleterious effect on mechanical properties, which can result in RPV embrittlement and limit reactor operation life. To understand the nanoscale precipitation mechanism, thermal aging at 370°C for up to 13200 h of high-copper RPV model steels was performed to produce nanosized Cu-rich precipitates. Then the Cu-rich precipitates were systematically investigated by atom probe tomography (APT). The changes in the mechanical properties of the steels were characterized by Vickers hardness test. The results show that the Cu-rich precipitates as determined by APT construction analysis have a spatial core-shell structure. The core is enriched with Cu atoms, and the region near the precipitate/matrix interface is enriched with Mn, Ni, Mo, and Si and C atoms. Cu-rich precipitates lead to precipitation strengthening and hardening/embrittlement effects. Using the Russell-Brown model, we estimated the hardening due to Cu-rich precipitates in the matrix and observed that the measured hardness and the estimated changes in hardness were in good agreement.

This article is devoted to the leaching of gold from copper-bearing oxidized stubborn gold ores in the Tarror deposit. The high copper content of the ores makes it difficult to extract gold from them by direct cyanidation. An analysis of the literature data indicated that ammoniacal leaching might be one solution to this problem. It is shown that the use of ammonia compounds in the cyanidation cycle makes it possible to obtain high indices for gold recovery without the accumulation of complex copper compounds in the solution. The amount of cyanide consumed in the production process is reduced accordingly.